James Kingston used his second round of 4-under 68 to move to 8-under-par 136, where he was joined by Stephen Gallacher, who shot a 70 on Friday.
Brett Rumford, Roger Chapman, Robert-Jan Derksen, Raphael Jacquelin and Steve Webster share fourth place at 7-under-par 137.
Lonard began his day at the first and picked up a birdie there. The Australian then dropped in an eagle at the par-5 second to jump to minus-11.
The 37-year-old Lonard stumbled to bogeys at the third and fifth to slip back to minus-9. From there, he reeled off seven straight pars around the turn at County Louth Golf Club.
Lonard picked up another birdie at the 13th, but bogeyed the very next hole. He moved back to 10 under with a birdie at the par-4 16th.
'It was a little tougher today and the wind came from a different direction,' said Lonard. 'There were a lot of approach shots played in a cross wind which made it a serious test. I got off to a great start and then hit some ordinary shots. The right-to-left breeze I struggled with a bit today and paid the penalty.'
Kingston stumbled to bogeys at the 11th and 12th to start his round. He came back with birdies at 13 and 18 to make the turn at minus-4 overall.
On the front side, Kingston sank five consecutive birdies from the second for the second straight day to jump to minus-9. He bogeyed his final hole, the par-4 ninth, to slip back to 8 under.
Gallacher bogeyed the 10th and 13th to open his round. He managed to birdie the 17th, but tripped to another bogey at the par-4 first. Gallacher fought back with an eagle at the par-5 second.
The Scotsman picked up birdies at the third and sixth to get to 10 under. He closed with three straight pars.
'I didn't feel I played that great, but it was played better yesterday,' Gallacher said. 'But I'll take 8 under at the halfway point. It was a lot tougher today. A different wind and a lot colder. It's early, a lot of golf to play, but if I keep chiseling away and keep thinking the same way, who knows.'
Miguel Angel Martin, Christian Cevaer, Stephen Dodd, Nick O'Hern and Peter O'Malley share ninth place at 6-under-par 138. Fredrik Andersson, Terry Price and Henrik Stenson are one stroke further back at minus-5.
The cut fell line at even-par 144 with 74 players advancing to the weekend.