Breakdown of À quelle heure ouvre la boulangerie le lundi ?
la boulangerie
the bakery
à
at / to / in (general locations) / about (what one thinks about / reacts to)
quel
which / what (adjective)
le lundi
the Monday
Questions & Answers about À quelle heure ouvre la boulangerie le lundi ?
Why use À quelle heure instead of just asking Quand ouvre la boulangerie?
Why does the verb ouvre come before la boulangerie?
In written or formal French questions, it is very common to swap the order and put the verb before the subject, especially after question phrases like À quelle heure. In spoken French, you might also hear people use est-ce que to keep the normal word order: À quelle heure est-ce que la boulangerie ouvre ?
Why does it say le lundi instead of just lundi?
Why do we need À at the very beginning of the sentence?
Because you are asking "At what time". In French, you use the preposition À (at) to talk about the specific time an event happens. If you dropped it and just used quelle heure, it would be used for asking the current time, like in Quelle heure est-il ? (What time is it?).