I do not believe there is any officially published schedule released by WDW for this as there are with other shows and attractions, I believe this information is only released to CMs on a weekly basis, that is what I recall when I used to be a WDWCM a few years ago.. The performers generally appear frequently up and down Hollywood Blvd.. More than likely you will see a performer as you walk by that area, but if you don't, then the best course of action would be to ask a CM in that area or Guest Relations and they should be able to give you more specific times, most of the CMs have pocket-sized schedules that they carry around for these kinds of questions..