I checked the jobbing.com arena schedule of events and there is a concert on Friday, May 18. I would guess the WCF would start on Monday or Tuesday with Game 2 on Wednesday or Thursday. Game 3 likely on Saturday night May 18?
The league would want to wait for the East to be at least close to being finished.
Total guess, but I'd say Sunday the 13th -- the last Eastern game possible is Saturday, and this way NBC gets their Sunday noon PDT game to show nationally while the Eastern survivors get a day to rest. The only conflict possible at the Job would be Rammstein on the 18th. If the NHL gets their schedule in before the NBA starts to schedule the Lakers/Clippers potential 2nd-round games, it could be a pretty straightforward schedule from the standpoint of arena availability:
@ Phoenix, Sun, May 13
@ Phoenix, Tue, May 15
@ LA, Thu, May 17
@ LA, Sat, May 19
@ Phoenix, Mon, May 21
@ LA, Wed, May 23
@ Phoenix, Fri, May 25
But hey, I'm making a guess from ZERO position of authority.