Robson and Nick Gubbins put on 51 for the first wicket after Middlesex had wrapped up the Nottinghamshire first innings with the second ball of the day when Harry Gurney was caught at backward point off Steven Finn.
The Middlesex openers seemed to have established a solid base on a pitch still offering lateral movement before Gurney got one to move back up the Lord’s slope and bowl the left-hander Gubbins for 23 in the 19th over.
Vernon Philander then nipped one back off the seam to bowl Nick Compton for three, leaving Robson and skipper Adam Voges to take their side to lunch at 70 for 2.
Middlesex are a batsman short after the club confirmed that Dawid Malan had broken a finger on the first day. His injury is being assessed later today.