The in-game description of Arcane Blade:
"As an Arcane Knight you can use any Hand weapon or Light weapon that deals additional fire, cold or shock damage.”
In context, Hand weapon refers to 1-H Weapons.
Since Mages can already equip Wands and Staves, Arcane Blade doesn't make sense. Unless you were eyeing that 2.5 damage multiplier. That would be insane when coupled with an elemental wand / staff.
If you're going for high elemental damage,, I might encourage you max out staff mastery.
Maxed Staff Mastery + High INT + Pure Elemental Staff = insane elemental damage.
On a side note, very low level mages can swap between wands and staves, but at some point you're going to want to pick one weapon type and master it. The mastery skill just offers such a nice bonus.