Rather, let me rephrase that.
The power of Blazing Arc is a free action triggered power that happens when you make an attack.
The property of Firewind Blade is an innate thing that just happens when you hit with an attack while wielding that weapon.
Doesn't work like that. The Blazing Arc focus is constantly active. Rules:
"You can add its enhancement bonus to the attack rolls and damage rolls of weapon attacks you make using a weapon with which you have proficiency. However, you must choose to use the enhancement bonus, properties and powers of the ki focus, rather than the weapon you're wielding, or vice-versa. You can't use both when you use a power."
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Twostuck, Homestuck RPG: http://www.gamefaqs.com/boards/8-gamefaqs-contests/62168402