How on earth have you lost control by loosing the one energy source ie the engine? You still have as much control as you would have with the engine albeit you will be trading altitude to maintain that control.
I would argue that without an engine in a SEP you have in effect lost control of the aircraft and if you are lucky and very skilled will be able to land it in a random field that is reasonably good terrain.
Well I think you are both wrong, so there!
So the truth lies in between.
When the engine fails patently you have less control given that you have lost the ability to control your height profile to the same extent.
Never the less you are still in complete control of the aircraft albeit not necessarily in complete control of where it lands.
Most PPLs are complacent about PFLs. In my experience they are rarely practiced and most PPLs will do well to land in a chosen field unless the field presents perfectly! It rarely does! That doesnt mean they will kill themselves because aircraft are surprisingly good at passing over ditches or through hedges!