If you turn left at this intersection, do you have the right of way over the vehicle approaching from the opposite direction?

No, when turning left, you do not have priority over the vehicle from the opposite direction. According to Art. 25 para. 1 of the Road Traffic Act, a driver must give way to a vehicle travelling from the opposite direction straight ahead or turning right. The visible warning sign A-5 "Crossroads" confirms that this is an intersection of equal importance where this general rule applies.