Hi Bruce,
the procedure we follow has been established by our LJ45 chief pilot..regarding several facts..
usually you have to taxi up to the deicing area, and during this part of taxi...flaps should remain retracted..to avoid overstress of any mechanical parts..specially when the plane was sleeping outside...
Then, only when the deicing process has been completed...a check of the propre operation (and clean status) of the flaps are conducted...
if a important taxi remains to be done, flaps are let in the up position..this to avoid penetration of snow, slush..etc...and keep a max of anti-icing fluid between the different parts...
Finally, when about to line up, we select the flaps position for TO..
The faa manual only states that the aircraft must be aerodynamically clean (quite obvious) before TO...this the approved part of the manual...
In the addendum part of the faa manual (which is not faa approved)..you'll see that in cold weather ops...it's better to taxi with the flaps in the up position...
All this to demonstrate the choice we made in our company...
The flaps are controlled for free operations only after deicing...and reset to up position...for further taxi...
regards..