As a conjunction:
* Quand: This is the most common translation and means "when" in the sense of time.
* Example: "When will you arrive?" --> "Quand arriveras-tu ?"
* Lorsque: This is a more formal synonym for "quand."
* Example: "When I was younger, I loved to play outside." --> "Lorsque j'étais plus jeune, j'adorais jouer dehors."
As an interrogative adverb:
* Quand: This is used to ask about time.
* Example: "When did you leave?" --> "Quand es-tu parti ?"
Other uses:
* Si: This can be used to mean "when" in a conditional sentence.
* Example: "When you are ready, we can leave." --> "Si tu es prêt, on peut partir."
* Dès que: This means "as soon as."
* Example: "When you get home, call me." --> "Dès que tu rentres chez toi, appelle-moi."
To translate "when" accurately, you need to consider the context of the sentence.