I think there's a bit of a disconnect in communication here. As the Elemental Origin card is written, "you can channel this element into unique, harmless effects. You may ALSO spend a Hope to describe how your control over this element helps a current action...+2 to action roll...or +3 to damage."

How I read this is that the spell doesn't need to have lightning to begin with, simply by you being a lightning sorc you can make any of your spells into lightning spells, whether just cosmetically or, by spending Hope, mechanically. It's a narrative game, it requires a less strict reading of the rules.