Yes, this works just fine. Once a creature is declared as a blocker, it remains a blocker until it is specifically removed from combat (e.g.  Regeneration) or the battlefield (e.g.  Cloudshift).

One thing to note: once a creature is blocked, it remains blocked even if the blocker is removed before damage is dealt. This works great against lifelinkers, since they deal no damage to a creature that is no longer there. It works less well on tramplers, since they just deal all their damage to the player instead.

Can I block with my Llanowar elves and then tap it for mana immediately afterward?
Is there any way to get a single wide desktop wallpaper to span a dual monitor setup in OS X?
