LIU is going to Division I about the same time as Merrimack.
This is not a new program either. Rather, it's the result of the merger of LIU-Brooklyn and CW Post into a single entity, with all sports moving to Division I as a result of said merger. CW Post currently has a Division II men's lacrosse program.
LIU and Merrimack are both moving to the NEC, which will give that conference nine men's lacrosse-playing members. It will be interesting to see if they follow the Patriot's lead and increase the conference tournament to six teams.