While I can't say I have any references at hand, this has been discussed a couple times, because...
Yes, regeneration is considered a form of healing, and yes, Divine Power is a Cleric power.
However, Healer's Lore only affects direct regular healing. Not regeneration. In actuality, this is the only difference between, say, a zone that restores hit points to allies whenever they start their turn within it, and a zone that grants regeneration to allies within it.
As I said, I don't have any reference at hand, but I believe it's in the CustServ FAQ.