That's a good idea, don't weed until you are certain. Chances are, many of the self sown hellebore seedlings will germinate before you are out and doing much weeding - some as early as December in my garden. (and don't worry about them, they are tough and don't need your intervention)

The helleborus cotyledons appear as follows - the next true leaf to form will look like a normal helleborus leaf in miniature.

Here is a link that might be useful: