Despite there already being an answer to this question, I thought the approach to it was wrong.
Divine Dazzle has an explicit effect on ranged creatures, and Stalker is not ranged. I used Warlocks to test the behaviour of this spell when the Warlock is invisible, and it has no effect.
That means, if there is only one Warlock and it is invisible, the spell goes on cooldown and does nothing at all. If there are multiple warlocks, it only hits those that are visible and turns them into melee creatures for 8 seconds.
Invisible creatures are thus not affected by Divine Dazzle in any way, you could say the spell doesn't know they are there!