The Republic of Ireland international has enjoyed two spells at Easter Road, scoring 33 goals in all competitions.
Stokes, who was signed by Lennon during his time in charge at Celtic, is currently a free agent following his release from League One side Blackburn Rovers.
Lennon, meanwhile, is keen to strengthen his attacking options after losing last season's top scorer Jason Cummings to Nottingham Forest.
"He's not been here, no," he told Sky Sports News. "There's no timescale [on signing Stokes]. The board are doing everything they can to try and make this happen so I compliment them.
"It's very encouraging from our point of view so I can't ask any more from the people behind the scenes."
When asked about the possibility of signing two strikers to replace Cummings, Lennon said: "Well, ideally yes, but that's not possible.
"We'll wait and see if any other opportunities arise but I think it's fair to say and it's been well documented that we are looking for another striker."
Hibernian have made seven new additions during the summer window as they prepare for life back in the top flight.