Hairstreak Butterfly

Here is some kind of Hairstreak on lesser daisy fleabane blossoms in my field.


(Click on image to enlarge)

I think it's a Banded Hairstreak. As in the case of the Duskywing, it's appearing at the right time but the wrong county; however, my butterfly book shows it in both Porter and Newton Counties, so what's to stop it from flying over the Lake County line? Its larval hosts are walnuts and oaks; plenty of oaks around here, anyway.