The United States international did not make a start in the Premier League for almost two months before an explosive performance against Burnley in October saw him score a hat-trick in a 4-2 win.
Further strikes against Watford, Ajax and Valencia followed, but Pulisic has not now registered a goal or an assist in his past four appearances.
Although Lampard has been pleased with his development, he will not let up in the demands he places on the £58million winger.
"I have just mentioned there about conversion of chances. I think he gets himself in so many good positions with his talent and his dribbling ability that I think more goals will be the next stage of that," Lampard told reporters ahead of Chelsea's meeting with Bournemouth on Saturday.
"I am really pleased with him. I have asked a lot of him. He has played a lot of games recently, back to back, in a new league that we know is very physical for him. I am asking a lot, but he has done very well. I expect a lot more."
Fikayo Tomori is one youngster to have impressed consistently for Chelsea this season, and the centre-back was rewarded with a new five-year contract on Thursday.
"He has come a long way, and that is all his own work," Lampard said. "From the moment he came to Derby County [on loan last season], he has shown a work ethic, a want and desire to listen and improve himself.
"His personality has come out even more. He was quite quiet when he first came to Derby; he is less quiet now.
"I think everybody saw his performances in the Championship last year, [he was] Derby Player of the Year. Then [there were] big question marks in the summer over whether he can do it in the Premier League.
"He certainly hasn't proved that yet over a period of time, which is the important thing. But from my point of view, I have full trust in him. I am delighted in him to where he has got to now.
"The important thing now is that he doesn't take anything for granted now that he has got that five-year contract. It is important that the hard work starts again. I am delighted with what he has done."
Lampard is similarly pleased with the progress of full-back Reece James, who has shown signs of real promise when deputising for Cesar Azpilicueta.
"I don't want to compare him to anyone. I just want to concentrate on Reece himself," Lampard said. "He's got a great role model in Azpilicueta, who has been doing it for years here in terms of how he's been playing in recent games.
"His attitude – talk about urgency and intention to get up and down the pitch and give everything and set the tone – I think it's great for Reece to see that as well alongside him every day. But Reece also brings a real quality in his delivery and in his forward play.
"There's work to do with him, he knows that, he's a young player. So, I think he's done really well on his first steps into the team. Again, like some of the other young lads, I expect a lot more from him because I can see the quality in him."