Quand le courant est revenu, Paul a rallumé la télévision, puis il a fini par l’éteindre pour lire.

In everyday French, le courant often means the electric current or simply the power supply.

So:

• le courant est revenu = the power came back
• il y a une coupure de courant = there is a power cut
• le courant est coupé = the power is off

A native English speaker might expect l’électricité, and that can work in some contexts, but le courant is very common when talking about electricity going off and coming back.

Est revenu is passé composé, which is used here for a completed event: the power came back at a specific moment.

So the sentence presents a sequence of completed actions:

1. the power came back
2. Paul turned the TV back on
3. he eventually turned it off
4. he read

If you used revenait (imparfait), it would suggest an ongoing or background action, which does not fit as naturally here. The return of the power is seen as a single event that triggers what follows.

The verb rallumer means to turn back on / relight, while allumer means simply to turn on / light.

The prefix re- in French often means again or back.

So:

• allumer la télévision = to turn on the TV
• rallumer la télévision = to turn the TV back on

Because the electricity had gone out, Paul is not just turning on the TV for the first time in the story — he is turning it on again once the power returns.

Puis means then, next, or after that. It helps show the order of events more clearly than a simple et.

So:

• Paul a rallumé la télévision, puis il a fini par l’éteindre
  = Paul turned the TV back on, then eventually turned it off

You could sometimes replace puis with ensuite or even et puis, but puis is neat and natural in written narration.

Finir par + infinitive is a very common French structure meaning:

• to end up doing something
• to eventually do something
• to finally do something

So:

• il a fini par l’éteindre = he ended up turning it off / he eventually turned it off

This structure often suggests that the action did not happen immediately. There may have been hesitation, delay, or a change of mind.

Other examples:

• J’ai fini par comprendre. = I eventually understood.
• Elle a fini par accepter. = She finally accepted.

L’ is the direct object pronoun meaning it, and it refers to la télévision.

So instead of repeating la télévision, French replaces it with l’:

• Paul a rallumé la télévision
• puis il a fini par l’éteindre

That literally means:

• Paul turned the television back on
• then he ended up turning it off

Because la télévision begins with a consonant sound, the pronoun would normally be la, but before a vowel in éteindre, it contracts:

• la éteindre → l’éteindre

In French, when a pronoun belongs logically to an infinitive, it usually goes right before that infinitive.

So:

• éteindre la télévision → l’éteindre
• finir par éteindre la télévision → finir par l’éteindre

This is very common:

• Je veux le voir. = I want to see him/it.
• Elle va nous aider. = She is going to help us.
• Il a décidé de l’acheter. = He decided to buy it.

So l’ is placed before éteindre, not before a fini.

For devices such as TVs, lights, phones, and computers, French commonly uses éteindre for turn off / switch off.

Examples:

• éteindre la lumière = turn off the light
• éteindre la télévision = turn off the TV
• éteindre l’ordinateur = shut down / turn off the computer

Fermer usually means to close, not to switch off. You can fermer la porte (close the door) or fermer un livre (close a book), but not normally fermer la télévision to mean turn off the TV.

Pour + infinitive is used when the subject of both actions is the same.

Here, Paul is the one who turns off the TV, and Paul is also the one who reads. So French uses the infinitive:

• il a fini par l’éteindre pour lire
  = he ended up turning it off in order to read

If the subject changed, French would use pour que + subjunctive:

• Il a éteint la télévision pour qu’elle lise.
  = He turned off the TV so that she could read.

So in your sentence, pour lire is the natural choice.

Yes, lorsque could also work here.

• Quand le courant est revenu...
• Lorsque le courant est revenu...

Both mean when the power came back.

The difference is mainly one of style:

• quand is very common and everyday
• lorsque is a bit more formal or literary

In normal speech and most ordinary writing, quand is extremely natural.

Both are correct, but the tone is slightly different:

• la télévision = full form, a bit more neutral or formal
• la télé = very common, everyday spoken French

So the sentence could also be:

• Paul a rallumé la télé...

That would sound more conversational. Using la télévision just gives the sentence a slightly more careful or written feel.

Yes, in context it can feel like both.

Literally, quand means when, but in a sentence like this, English might naturally translate it as:

• When the power came back...
• Once the power came back...
• After the power came back...

The French still uses quand, but the exact English wording depends on what sounds most natural in context. Here it introduces the event that makes the next actions possible.