Learn Hardcore French: Quand Paul crie, sa sœur ne cache plus sa colère. - When Paul shouts, his sister no longer hides her anger.

The French present here corresponds to the English present simple used for habits. There’s no special “habitual” tense; the ordinary present does the job.

What is the role of quand here? Could I use lorsque instead?

Quand introduces a time clause: When / Whenever Paul shouts…

Quand is the most common everyday word for when (in the sense of at the time that).
Lorsque can usually replace quand in this kind of sentence and sounds a bit more formal or literary:

Lorsque Paul crie, sa sœur ne cache plus sa colère.

Both are correct. In speech, quand is more frequent.

Why is the word order Quand Paul crie, sa sœur... and not something like Quand crie Paul?

French normally keeps subject + verb order, even after words like quand:

Quand Paul crie = When Paul shouts

Putting the verb before the subject (Quand crie Paul) sounds poetic, old-fashioned, or just odd in everyday French. In questions you can invert (Quand Paul crie-t-il ?), but in a normal statement you don’t.

How does the negative ne ... plus work in ne cache plus?

Ne ... plus means no longer / not anymore.

cacher = to hide
elle cache sa colère = she hides her anger
elle ne cache plus sa colère = she no longer hides her anger / she doesn’t hide her anger anymore

Compare:

ne ... pas = not
- elle ne cache pas sa colère = she does not hide her anger (no idea if she used to)
ne ... plus = no longer
- elle ne cache plus sa colère = she used to hide it, but not anymore

Why is it sa sœur and not son sœur?

French possessive adjectives (mon / ton / son / ma / ta / sa) agree with the gender and number of the noun possessed, not with the person who owns it.

sœur is feminine singular → you must use sa:
- sa sœur = his sister / her sister
son is used before masculine singular nouns (or before some feminine nouns starting with a vowel sound):
- son frère = his brother / her brother

So regardless of whether it’s “his sister” or “her sister” in English, French uses sa sœur because sœur is feminine.

Why is it also sa colère? Does sa still agree with the noun?

Yes. Again, sa agrees with the noun that follows:

colère (anger) is feminine singular
therefore: sa colère = her anger / his anger

So in the sentence:

sa sœur → the noun sœur is feminine, so sa
sa colère → the noun colère is feminine, so sa

French doesn’t show whether the possessor is male or female here; context tells you.

Could sa colère mean someone else’s anger (not the sister’s)?

Grammatically, sa colère just means his/her anger, referring to the most logical person in context.

In this sentence, the structure:

sa sœur ne cache plus sa colère

strongly suggests that both “sa” refer to the sister:

Paul shouts
his sister (subject of the second clause) no longer hides her anger

If you wanted to clearly say she doesn’t hide Paul’s anger, you’d normally rephrase:

Quand Paul crie, sa sœur ne cache plus la colère de Paul.
(When Paul shouts, his sister no longer hides Paul’s anger.)

What exactly does cacher sa colère mean here? Is it like “to hide one’s feelings”?

Yes. Cacher sa colère literally means to hide one’s anger, and idiomatically:

to conceal that you’re angry
to not show your anger, to keep a straight face

So elle ne cache plus sa colère = she stops pretending she’s not angry; she shows it openly (through words, tone, expressions, etc.).

Why isn’t there an article like la before sœur or colère?

In French, possession is usually expressed with a possessive adjective, not an article + “of” phrase:

sa sœur = his/her sister (not the sister of him/her)
sa colère = his/her anger

You wouldn’t say la sœur de lui in normal speech; you use sa sœur instead. The possessive replaces the article (la, le, les).

How is the sentence pronounced, especially crie, cache, and plus?

Approximate pronunciation (in IPA):
Quand Paul crie, sa sœur ne cache plus sa colère.

/kɑ̃ pɔl kʁi sa sœʁ nə kaʃ ply sa kɔlɛʁ/

Key points:

crie → /kʁi/, like “kree” (no sounded final -e)
cache → /kaʃ/, like “kash” (the -e is silent)
plus in ne cache plus → usually /ply/ here (no final -s sound) when it means no longer
final -r in colère is pronounced /kɔlɛʁ/ (French “r” at the back of the throat)
Quand → /kɑ̃/, nasal vowel (not “kan” with a clear “n”)

In spoken French, is the ne in ne cache plus often dropped? Does that change the meaning?

In everyday spoken French, people very often drop ne:

written/standard: sa sœur ne cache plus sa colère
common spoken: sa sœur cache plus sa colère

The meaning is intended to be the same: no longer hides.

However, there is a potential ambiguity in theory:

ne ... plus = no longer
(no ne) + plus can also mean more in other contexts

In practice, the context and the pronunciation help:

plus meaning no longer is often pronounced /ply/ (no “s” sound)
plus meaning more can be pronounced /plys/ (with the “s”)

But the presence or omission of ne is the main difference between careful standard French and casual spoken French.

What is the difference between ne cache plus sa colère and montre sa colère?

They are close in meaning but not identical:

ne cache plus sa colère emphasizes that she stops hiding her anger (contrast with before, when she used to hide it)
montre sa colère means she shows her anger, without explicitly mentioning any change from the past

So:

Elle ne cache plus sa colère. → she used to hide it; now she doesn’t anymore.
Elle montre sa colère. → she shows it (maybe she always did, maybe not; context needed).