The problem is.
Lumiere is WK level Light user.
Which happens to be the only counter for Time Magic that exists.
What do you think about this argument?
Well, certainly Light Magic seems to not be the best of match-ups against Time Magic, and if we're talking about Lumiere is even worse as he should be far more powerful and faster than Patri. At first sight, it doesn't seem plausible that Julius would be able to win against him given his feats against Patri and how he claimed to be having a hard time catching him.
I think Julius would be able to keep up due to his foresight (best of the verse currently) and Mana Zone. As for landing hits... not gonna lie, it would be hard and even being serious, Lumiere could probably hit him sometimes (he could insta-heal with Time Reversal though).
It's hard for me to argue in Julius' favour with his current feats and arguable match-up disadvantage, but I think we've only seen the tip of the iceberg when it comes to Julius' abilities. His grimoire seemed to have a lot of pages, so I'm pretty sure he has more techniques we've yet to see since he hasn't gone all-out, arguably even more broken than his Time Annihilation and I think that used right, it could potentially give him the edge against Lumiere.
As of now though, Julius loses against Lumiere most likely, and I don't think Hellfire Mereoleona is on the level of Prime Licht and Lumiere yet (I don't think she's too far personally tbf).