If you are attacked by something after being frozen, the ice breaks (although visually it still seems like it's there). That's why you are still able to move.
Well from as much as i have fought against him i realized this:
If Toshiro freeze you, you cannot do basic attack (for assoulters, since his skill disarm only assoulters). But if assoulter have enough fury for his skill, he still cast his skill.
Atleast that's what i remember from fighting him.
PS
I hope you asked about Toshiro from Special War Power