Here I am, late to the party, after quaffing a very couple or four of pints down the Old Mitre (Hook Norton "Twelve Bells" - cracking stuff). Anyway:
WHEREUNDER: The NDER is from RENDER (perform) which has U (turn) stuck in it.
INFRARED: Invisible isn't another word for infrared, it is a quality of infra-red, by definition really - if it is visible it isn't infra-red. I'm sure there's a scientific definition somewhere of what range of wavelengths are considered "visible" and at lower frequencies, which are "infra-red" (before moving onto microwaves etc.).
For ARISE: The insertion indicator is simply the "of" in the clue - happens sometimes.
Oh dear, this "Bah Humbug" T-shirt is going to need a wash before next year.
Toodle pip!