Speaking ahead of Celtic's Europa League play-off clash with AIK of Sweden, Lennon said: "We are working to bring three or four players in before the window shuts."
Jonathan Afolabi joined the club yesterday following his release from Southampton, but the Hoops manager is still keen on bolstering his squad before the deadline.
Bournemouth winger Jordan Ibe, and Rosenborg defender Birger Mei
The champions have also brought in Christopher Jullien, Boli Bolingoli, Hatem Abd Elhamed and Luca Connell.
Elhamed remains doubtful for the visit of Rikard Norling's side, while Tom Rogic is back in training but won't be involved.
Lennon added: "Hatem is a doubt for tomorrow. Tom trained for the first time today, which is a real positive but too soon for him. The rest of the squad is healthy."
The former Hibs head coach also called for a "sense of balance" from critics, insisting: "It's not me that is creating the headlines or shouting out the criticism. There has to be a sense of perspective. There's a little bit of hysteria around things at times.
"That is the environment you're in in Glasgow sometimes.
"We've lost one game, and we scored three goals in it, so it's not all doom and gloom.
"There's a narrative that we are maybe a little off-colour. We're absolutely not - we're fine. Hopefully the players can go out and show that.
"People are entitled to criticise me, the players, but there has to be a sense of balance."