Are you the date is correct. May 19 2011 was on a Thursday yet HSM 3 aired the next (Friday) at 8/7c and lemonade mouth also aired at 8/7c on Friday. Makes no sense. Maybe it was May 18?
dcba.fandom.com/wiki/May_19,_2011 This is my source, on why it's May 19, 2011 (you can also check the cited Zap2it page at the bottom in the "sources" tab). It's the airings at 1-2am. Networks usually don't switch over promos to reflect the new day until 6am (EST) for the most part... Hence why the HSM3 Senior Year promo isn't saying "tonight".