Have added women's lacrosse since 2015 or are slated to add women's teams without adding a men's team or having one already onboard. Per The Growth Blog, in addition to Pitt, that list includes:
Akron
Arizona State
Butler
Central Michigan
Dayton
East Carolina
Kent State
Radford
VCU
Wofford
and maybe a few others I'm missing. Hard to believe that all of them had Title IX issues. And if that isn't the case, I would have liked to have seen those schools add men's lacrosse as well.