Can you lay subfloor on concrete before framing interior walls?
I think you can do both, but framing walls on top of subfloor is potentially less work.

If you use a product like DriCore for the subfloor, they even explicitly recommend you frame on top of their subfloor product. They do, however, recommend you screw the framing through the subfloor into the concrete with something like 3" Tapcons spaced every 4 ft through the bottom sill of the framing.