These two photos of the same, fresh, imago show the yellowish tinge to both the   underside, and also dusting the upperside basal area. The hindwing underside shows the two arc shaped spots in S1 and S2. The upperside does not, I'm afraid, show the well marked hidwing also typical of this Pyrgus.

This butterfly was photographed in early July in the Haute-Savoie. where I have seldom knowingly met up with it.