Learn Hardcore Italian: Il cielo nuvoloso nasconde le stelle per qualche minuto. - The cloudy sky hides the stars for a few minutes.

This is a reduced relative clause. The full idea is il cielo che è nuvoloso (the sky that is cloudy), but Italian often omits che è, leaving simply il cielo nuvoloso.

What is the subject of nasconde and why is the verb singular?

The subject is the noun phrase il cielo nuvoloso, which is singular, so the verb nasconde is in the third-person singular present tense of nascondere (to hide).

Why do we use le stelle instead of just stelle?

In Italian, definite articles are generally used before plural countable nouns. Le is the feminine plural definite article that matches stelle (stars), hence le stelle.

What does per qualche minuto mean, and why is minuto singular?

per qualche minuto means for a few minutes. Qualche always takes a singular noun, so you say minuto (singular) instead of minuti (plural).

Could we replace qualche minuto with alcuni minuti? Is there a nuance?

Yes, you could say per alcuni minuti. Both mean for a few minutes, but qualche minuto feels a bit more indefinite, while alcuni minuti is a straightforward plural form.

Why is per used to express duration here rather than da?

To indicate how long an action lasts, Italian uses per. Da is used for when something has been happening from (e.g., da tre minuti means for/ since three minutes ago).

Can the adjective nuvoloso ever precede the noun cielo?

While you might see nuvoloso cielo in poetry or for emphasis, the neutral, everyday order is cielo nuvoloso (noun + adjective).