In The Garden: Help Identifying my Hydrangea?

Does anyone have any advice/leads on helping my identify this Lacecap Hydrangea that I have in my front yard? I've got two of them that I acquired with the house - it would've been something faily generic, as it's one of the few plants the builder of the house planted (probably from Home Depot, I'd imagine).

There's so many varieties, my internet searching has overwhelmed me. I keep a catalogue of my garden, and this is one of the few plants that I've kept from the original builder's half-assed landscaping.

 

I'd add another pic when the bloom is fully open as it looks only partially open.

 

Good point - here's a photo from yesterday, with the bloom a little further along.