Hello,
Have a 15 year old Norfolk Pine that was reasonably healthy as an indoor plant except that every time it had a growth spurt it would lose it's lowest rung of branches.
Recently repotted it and moved it outside in a pot with good drainage.
Recent cold snap (-5 degrees C) has it turning brown and drooping badly.
I want to bring it inside again, but don't want to shock it.
Advice?

I would bring it indoors, I don't think it can take that kind of cold (-5C = 23F - I'm guessing you're not in the USA since you use C).

I suspect your tree might already be dead. 10c (50F) is about as low a temperature as Norfolk Island Pines can survive. Give it the scratch test to be sure: scratch the bark with your fingernail or something with an edge (butter knife?). If the layer under the bark is green, your tree is alive. If its brown, your tree is dead.

I'm afraid Daisy may well be right but trying to be optimistic, if it was near the house and sheltered, for example, it might not quite have experienced -5C. According to this Florida production guide for Norfolk Island Pine:

"Norfolk Island Pine will tolerate a wide temperature range. High temperatures (95° to 105°F) have been observed to cause noticeable tip damage if accompanied by dry winds and clear skies, whereas low temperatures (30° to 32°F) can cause growing point abortion. Temperatures below 25°F can cause severe freeze damage, especially if accompanied by wind. Suggested production temperatures are 60° to 90°F for seedlings and liners and 45° to 90°F for potted trees."

From:
http://mrec.ifas.ufl.edu/folia...