Can you conquer and score a battlefield on your opponent's turn if you controlled it at the start of their turn but lost control during their turn?

Ruling: Yes, you can conquer and score a battlefield on your opponent's turn if you lost control of it during that turn, as long as you haven't already scored it that turn. You must lose control before you can conquer again.

Sequence:

• You control a battlefield at the start of opponent's turn
• You lose control of that battlefield during opponent's turn
• You regain control of that battlefield during opponent's turn (via effects like Ride the Wind)
• You conquer and score the battlefield

Nuances:

• You cannot score a battlefield you've already scored that turn
• Successfully defending a battlefield (opponent contests but fails) does not count as conquering - you must actually lose and regain control to score again
• This is different from 2v2 rules regarding teammate-controlled units