His seven-under-par 65 in the second round of the $75,000 Journey to Jordan #1 was motivated by a terrible finish on the opening day.
One-under through 16 holes in windy conditions on Monday, the 22-year-old made a triple- bogey 8 at the 17th and a bogey on the 18th.
“The finish yesterday really frustrated me, but it also fired me up to come out and play well today," said Lumsden, who turned pro last year after a successful spell at Northwestern University in Chicago.
"I was very happy with the way I played. I was pretty good with my wedges and hit a few to tap-in distances.”
Heading into the final circuit, Lumsden sits joint-second, one shot behind England's David Langley, who is bidding to make a winning debut on the Arena-sponsored circuit.
Sixteen-year-old Jordan amateur Shergo Al Kurdi is alongside Lumsden, as are Swedish pair Per Langfors (69) and Calle Strandberg (68) and England’s Tom Sloman (67).
Sam Locke, the joint-ovenight leader, slipped to a tie for tenth on one-under following a 73. Scott Henry is on the same mark after a 71.
Craig Ross (one-over), Conor O'Neil (three-over) and Calum Fyfe (six-over) are also inside the top 40 as all five Scots in the field made the 36-hole cut.
Elsewhere, former Scottish Boys' champion Connor Wilson sits in the top 10 at the halfway stage in the African Amateur Stroke-Play Championship at Leopard Creek.
The Castle Park man carded a three-under-par 68 in the second round at the European Tour venue for a share of seventh spot on three-under.
South African junior Ryan van Velzen, with rounds of 64-66, leads by seven shots from compatriot Martin Vorster and Ireland's James Sugrue, the Amateur champion.
Also in South Africa, defending champion Jane Turner is handily-placed after day one in the SuperSport Ladies Challenge.
She sits joint-fourth, two shots off the lead, after carding a four-under-par 68 at Lost City Golf Club in Sun City.