In theory it will be best to chop late winter/early spring when there is no risk for frost, and prior to bud swelling.
It is important with no frost especially if the tree is placed outside, since trees in general is storing the sugars in the trunk, branches etc, which translates into cold-tolerance. By removing branches in the height of winter, your will be lowering the cold tolerance of the tree, and you will risk it dying, if the temperature gets too low.
Chopping prior to bud swell because the tree uses its sugar storage to push the buds - if you do later, the tree would have spent the energy pushing those buds, which you will then cutoff before it gets its investments back, and the tree will be in energy negative for the rest of the year.