When you come back to me

Just afloat * on the sea
Find myself on a page of history
You know as I ride along
I can always hear the song
About you and where you’re meant to be *

You’re gonna * tell me the answers
I’ll know when you come back to me*

If we should fall, love will catch us every time
I hear you call, I will run
And if the magic of the adventure overcomes *
We won’t cry because it could be fun

Well, I’m gonna tell you the answers
You’ll know when you come back to me

And I’m gonna be alright
When you come back to me

* I’ll know when you come back to me – future time clause  
_ Structure = when + present simple, future
future + when + present simple

The structure is the same with before, after, as soon as and until. It’s also pretty much the same structure as the first conditional (with if instead of when):

  • If it rains, we won’t go to the beach.

  • She’ll buy a new car if she gets the job.

In this structure, the future can be expressed in different ways:

  • will future
    When they arrive, I’ll call you.

  • be going to
    I’m going to be alright when you come back to me.

  • may/might (to express a possibility = Maybe you will do something.)
    When you finish this book, you might want to see the movie.

  • the imperative
    Call me when you get there.

_ Common mistake = ++ I’ll call you when I will be at the airport. ++
=> NO NO NO!!! => I’ll call you when I am at the airport.

The idea that you express is indeed that of a future action. However, in English, you cannot use the will future after ‘when’ (if when is a conjunction – stay tuned, next week and the week after, we’ll see more of that!).
If you are a Spanish-speaking person, think about what you’d say in Spanish and you’ll realize that it’s almost the same: no future (=> subjunctive).

There are obviously hundreds of other songs with this structure but here’s another one:
Garbage – When I grow up