Orr found trouble on the ninth when he hooked his approach into thick rough down the left and, despite pitching to six feet, he missed his par putt.
At ten under he was one ahead of Lynn – whose only European Tour victory in 350 starts came in this event back in 2004 – with McIlroy, Kingston and Irish Open winner Dyson slipping to eight under.
Orr was making a string of clutch putts to save par, but twice winner Dyson birdied the 12th and 13th before firing his approach to five feet on the 14th.
By completing a hattrick of gains he was now one in front of Orr, with Lynn, McIlroy and Kingston three off the pace.
After 11 holes without picking up a shot, Lynn was suddenly right back in it when he eagled the 12th from ten feet to be only one behind.