It is possible to have positive lift on the tailplane.This condition is met if the CG is aft of the centre of lift of the wing (roundabout quarter chord point) but not too far behind.This is because the combined wing plus tailplane centre of lift must remain ahead of the CG in order to ensure positive static stability.
I can assure you of this fact from experience.Many many years ago,as a flight test observer I was given the task of flight testing a so called tail load restrictor in a Lancaster.It simply froze the power controlled elevator motion when a certain upward tail load was reached (designed for bombers recovering too smartly from evasive manoevres).I tested over a range of CG's and at the aftmost the inevitable happened--we pulled sufficient g to lock the elevator in steady flight, but couldn't push the stick forward, because that would transiently
increase the upload further.Fortunately I had the foresight/luck to install a cut-out switch (I can see it until this day)
Keith