I think that this tiny beauty is a Silvery Blue --
I've seen them around for years and never managed to photograph one. The topside of their wings is quite blue -- unfortunately, they flitter around very quickly and when they do alight, their wings are folded, showing the pretty silvery-blue underside.
Also, they stay close to the ground -- and it's not easy for me to get down to that level quickly. By the time I do, the fickle thing has moved on.
Plus, they're tiny. For reference, that's a hosta leaf this one is sitting on. Still, I'm glad to have an idea what they are. You can biggify the first picture to see his classy striped antennae. Or you can go HERE to see some better pictures and more information.