These clauses express an impossibility with regard to the past. (When we will receive our marks, we will go on holidays) (When I'll come back, I'll go to the Eiffel tower)
When you want to express a certainty, you use quand + future simple Si tu as des problèmes, appelle-moi ! (If you have any problem, call me !).Si tu sors, mets ton manteau ! (If you go out, put a coat !).To express an advice or recommendation, you use si + present + present imperative To express a fact, a generality, you use si + present + present Elle lui demande si elle viendra avec nous.Si is never used after the future, do not confound the indirect speech that uses the future to the assumption that cannot use it.
(If I leave sooner, I'll come to see you) (If I come back to Paris, I will go to the Ritz)
