In fairness, the points that TonyW is making have some merit:
a) that a player in his own half cannot be offside.
b) that there are different passages of play that affect whether there is an offside offence committed.
However, he is misapplying these points because:
a) The offside law relates...
Yes, Mind you, he doesn't need to even play the ball for there to be an offence. If he runs away from the ball, drawing a defender away, to create space for a team mate to receive it, he would be deemed to be interfering with an opponent.