hennes just solved the mystery of the LampShade That Wouldn't Come Off. So now instead of an ancient 20w CFL that took a half-hour to warm up and cast an orange glow over everything in the living room, I have a 25W daylight-spectrum CFL that looks a bit bluish in comparison. Luckily the fitting was ES (European Screw) rather than bayonet like some fittings are in this country (and indeed in this house). I don't really feel guilty about the higher wattage because this means we will use the 300W uplighter far far less.
Yay. It appears significantly brighter. If you haven't tried CFL bulbs for a few years and previously found them too dim it's well worth trying again. I usually get the ones that have the skinniest tubes, because they seem to be best at getting to full brightness quickly.