Polyommatinae? This was in a sub-alpine meadow. Plants blooming there included white clover, Thermopsis montana (false lupin or whatever you prefer to call it), and yarrow, plus what I've forgotten in the last month. There were a fair number of blues like this. The next two pictures I'm going to upload were in the same place three days later and I think they were the same species, but I'm not sure.

Sorry it's out of focus.