I think almost every good shooter would agree that you want to begin your draw with your drawing forearm and elbow in line with the arrow, regardless of the position of the bow when you begin your draw.
The way I preset before I begin my draw is to extend my bow arm in the direction of the target at about a 45* downward angle. This puts a little tension on the string. Different archers use different preset positions. Of course, since I want my string forearm and elbow in line with the arrow, that means they are also at about a 45* downward angle at that point in the draw.