Two Future sentences.

[Verona_82]

5jj, in our (I mean my country's) grammars such sentences are referred to as "first conditionals" or "real conditions" (if + present). My teachers and tutors have always referred to them like this.

[5jj]

5jj, in our (I mean my country's) grammars such sentences are referred to as "first conditionals" or "real conditions" (if + present). My teachers and tutors have always referred to them like this.

if-clauses: conditional
when-clauses: temporal (or time).

Are you sure that your grammars call when-clauses conditionals?

[Verona_82]

Oh my.
Of course they are temporal! We're talking about "when".
Sorry Sunday evening syndrome...

[5jj]

Sorry Sunday evening syndrome...

Sunday evening syndrome. SES.
I like that.
If you look back through my posts, you'll see that I appear to suffer from occasional MES, TES (twice a week) WES, FES and the second SES.

[Kotfor]

I will look at Part 1 of your OP in this post:
I agree with mykwyner.

In this case I can clearly discern two different meanings in this sentence.

I will tell you when he comes. MEANS

1) I will tell you (about something) when he comes.
2) I will tell about his coming as soon as he comes. (as fivejedjon and mykwyner pointed out its meaning)

Two meanings are quite different.