I'm a Louisville fan and thought I'd chime in with a few thoughts (as this topic interests me quite a bit)
UofL fully funds all of its athletic programs so its scholarship break down (at present) would look something like this
Men’s scholarships
Baseball = 11.7
Basketball = 13
Cross Country and Track and Field = 12.6
Football = 85
Golf = 4.5
Soccer = 9.9
Swimming and Diving = 10
Tennis = 4.5
Total = 151.2 (51.75% of all athletic scholarships)
Women’s scholarships
Basketball = 15
Cross Country and Track and Field = 18
Field Hockey = 12
Golf = 6
Lacrosse = 12
Rowing = 20
Soccer = 12
Softball = 12
Swimming and Diving = 14
Tennis = 8
Volleyball =12
Total = 141 (48.25% of all athletic scholarships )
Right now, UofL is compliant with all three areas of Title IX (participation, treatment, financial assistance). If UofL did decide to sponsor men's lacrosse, that would add 12.6 scholarships to the men's side and swing the men's scholarship percentages up to 53.75%. That might be enough of a bump to move UofL out of compliance with Title IX (I say might because figuring out if a school is compliant or not is a complex process and involves a lot of gray areas; e.g. what's considered "substantially proportionate").
If Louisville is required to sponsor a new women's sport to maintain gender equity, then things get a bit more complicated. Cost is always a concern when adding multiple new programs, though I don't think that that will be the main issue (the athletic department already has a very healthy revenue stream at present andthings will only get better with the move to the ACC). The biggest issue in my opinion is the fact that Louisville already competes in all of the women’s sports currently sponsored by the ACC. This means that any women's program added by UofL might be forced to find a conference home outside of the ACC (something that Jurich is not very keen on doing).
One potential solution to this issue might be to sponsor women's gymnastics. NCAA bylaws state that at least four institutions must sponsor gymnastics in order for a conference to hold a conference championship event. The ACC had planned to sponsor women's gymnastics as a 4 member conference sport but with Maryland leaving and only three potential member remaining (Pitt, UNC, and NC State), those plans were put on hold. If UofL had to add a women's sport to balance out the addition of a men's lacrosse team, then sponsoring women's gymnastics would not only keep UofL Title IX compliant but would also help the conference out as well.
With that said, I'm not sure how big of an issue Title IX will actually be. If you compare UofL's athletic department to UNC's, you'll find that UNC sponsors three more men's programs (lacrosse, fencing, and wrestling) than UofL but only two more women's program (fencing and gymnastics). Additionally, women make up a higher % of UNC's student population (58%) than they do of UofL's (52%). These two things lead me to believe that UofL might be able to add men's lacrosse only without having to worry about adding a corresponding women's sport.