Philippe Saint-Andre takes his side to Twickenham this weekend under pressure from various quarters, but Lancaster has called on his players to remain focused.
"If you look at their performances in the autumn, the three wins over Samoa, Argentina and Australia show they are not a bad side," Lancaster told Press Association.
"They beat Australia 33-6 and Australia then beat us. While we'll take something out of their first two Six Nations games, we'll also take something out of those autumn internationals and make sure we're ready for them."
England are the only team still capable of winning the Grand Slam.