This is the 2292nd most frequent French word.
lorsqu
"Lorsqu'" means "when" or "while."
Here, 'lorsque' begins a conditional clause denoting time dependence.
Lorsqu'il pleut, je préfère rester à la maison.
When it rains, I prefer to stay at home.
Here, 'lorsque' is used to mean 'when' referring to a specific circumstance in time.
J'attends patiemment lorsqu'il est occupé.
I wait patiently when he is busy.
In this sentence, 'lorsque' introduces a situation during which something happens.