This paradox is messing with my mind. Elsa never lived at the Duke's mansion in the previous timeline, right? Otherwise Yvonne would have remembered it. On the other hand, it's clear that the reason why Yvonne's mother survived in the previous timeline is because of Elsa's power.
It's really tough to wrap my head around... The Witch Elsa did state that the present was already set in stone and could not be changed, so does that mean that everything happening in the past now also happened in the previous timeline? If that's the case, why did Yvonne forget about Elsa? How did Elsa end up in an orphanage when she was so loved by the people at the Duke's mansion?