Future Simple. Use # 7: No Future in Time Clauses
Like all future forms, the simple future cannot be used in clauses
beginning with time expressions such as:
when, while, before, after, by the time, as soon as, if, unless, etc.
Instead of simple future, simple present is used.
Incorrect: When you will arrive tonight, we will go out for dinner.-
Когда вы приедете сегодня вечером, мы пойдем ужинать.
Correct: When you arrive tonight, we will go out for dinner.- Когда вы
приедете сегодня вечером, мы пойдем ужинать.
