I want to use Wintertouched + Lasting Frost as a sorcerer, but I don't like many of the Cold Sorcerer powers. Can I make my Implement attacks do cold damage with a Frost dagger? Or does that only work with Weapon attacks?
The Frost weapon does not specify that it applies to only weapon attacks. It says:
All damage dealt by this weapon is cold damage. Another free action returns the damage to normal.
That means all, even implement damage.
The contrast here is between damage dealt "by a weapon" (includes weapon and implement powers), and "by weapon attacks" (or similar) which would only include weapon attacks.