This weakens Lorraine’s argument. If people become better-informed after referenda are introduced, then the referenda would be less likely to lead to disaster.

This neither strengthens nor weakens Lorraine's argument. Lorraine has already stated that the general public doesn’t know much about foreign policy overall, not that they are better-informed about the outlines versus the specifics or vice-versa.

If referenda would make it impossible for France's allies to make reasonable decisions, this strengthens Lorraine's claim that referenda will lead to foreign-policy disaster.

We don't know that the referenda would actually require a minimum amount of signatures. But if they did, and this answer choice were true, then the public would likely become better-informed, and referenda would be less likely to have negative results. This would weaken Lorraine's argument.

This is more relevant to Claude's argument than Lorraine's. Lorraine's argument isn't about whether elections constitute a public mandate for foreign policy decisions, just about the likely outcomes of introducing referenda.