Learn French: Pendant que le soleil brillait, un orage a éclaté. - While the sun was shining, a storm broke out.

This sentence perfectly shows how these two tenses work together! The imparfait (brillait) sets the background scene (the sun was shining), while the passé composé (a éclaté) is used for a sudden, completed event that interrupts that background (a storm broke out).

Why is pendant que used here instead of just pendant?

You use pendant (during) before a noun, like pendant le film (during the movie). But if you want to say 'while' and introduce a full action with a subject and a verb (like le soleil brillait), you must use pendant que.

Is there a trick to remembering that orage is masculine (un orage)?

Yes! In French, almost all nouns that end in -age are masculine. So just like un fromage (cheese) or un voyage (trip), you say un orage. One of the rare exceptions to watch out for is une image!

The verb éclater means to explode or burst. Why is it used for a storm here?

In French, éclater is the standard verb used when sudden, intense events start. So for a storm (un orage), a fire, or a war, a éclaté is the natural way to say it broke out or started suddenly.