I opted to skip the honorifics for this one because "aneue" (姉上) is less commonly known than "onee-san" or "onee-chan." The former is just a more formal and archaic version of the latter.
At any rate, Oscar's idol arc has begun.
What is this...?Oh my! Congratulations!Application MotiveWhat is the matter, Oscar?Sister.The thing is, I just received this."Idol Acceptance Audition Notice"...?But I don't remember sending an application for such an event.It must be a mistake...Oh!Actually, I'm the one that sent the application.I thought you must absolutely participate.I still have other application letters...Sister!?