When you reach Talmberg for the first time, Olena won't count as your horse anymore (no access to its inventory, no whistling it etc.), just as any other horse.It has infinite courage and health (this is so that the Cumans chasing you don't kill Olena or make it bolt. As soon as you mount it for the first time at the beginning of the quest Run!, Olena will be treated as your horse - you can whistle it, access its inventory, it cannot die (can only be knocked out) and you can equip horse tack.Olena behaves differently throughout the quest Run!:.Olena still won't count as your horse though. If you don't flee Talmberg with Olena, it will stay at the same location once dismounted and will remain there, so Olena can be used as a mount until you unlock Pebbles during the quest The Hunt Begins (this needs verification - may have been patched in update), or you have enough money to purchase a horse from one of the three Horse Traders located throughout the land, you just have to get back where you left it last time and mount it.Olena was a horse that Henry stole in order to flee the attack of Skalitz.
Skalitz For the wife of the Talmberg fisherman, see Olena.