The Spaniard started the day with a two shot lead and while he bogeyed his opening hole in round three, he responded with six birdies to sign for a 66 and sit at 16 under.
Elvira's sensational play in South Wales represents a stark change in fortunes for a player who finished 149th on the 2020 Race to Dubai Rankings in Partnership with Rolex after four consecutive seasons in the top 75.
He had made just two of his last 11 cuts coming into this week but has rediscovered the form that made him a four time winner on the European Challenge Tour and is in pole position to become the season's third wire to wire winner after Bernd Wiesberger and Lucas Herbert.
"It’s a good feeling," he said after opening up the biggest 54 hole lead of the season. "But to be honest, I don’t care at the moment. I struggled a bit the last year, year and a half, not with form but it’s golf - mentally, a little bit physically, battling with an injury. I’m happy playing golf again and being in the moment.
"I struggled a bit this year. To be in contention is a gift. It shows that the work I’ve been doing is paying off. We don’t know what’s going to happen tomorrow but I’m happy with the way I am to be honest.
"I’ve watched so many clips of Seve (Ballesteros). He’s an inspiration. We’re from the same town, I’m from the North, and I’ve always looked up to him. He’s an inspiration to so many players.
"Also José María (Olazábal), we get to see him every now and then at tournaments. He always has good advice and he’s the nicest guy. To have him around is fantastic. I wish I could follow their footsteps, but it’s a little bit far away.
Elvira three putted the first but got up and down after failing to reach the green at the par five second in two and never looked back.
The 34-year-old holed a 15 footer at the fifth to get into red figures for the day and with closest overnight challenger Vincent Norrman making a double bogey on the sixth after finding water off the tee, the advantage was five shots.
To be in contention is a gift. It shows that the work I’ve been doing is paying off
The leader got up and down on the par five ninth and hit the green in two at the par five 11th to keep his five shot cushion but the group in second was growing as Korhonen made birdies from around eight feet on the fifth and eighth and added another from the fringe on the 13th.
But it was soon a one man club as Shinkwin signed for a sensational eight under par effort.
The 28-year-old made the most of the second, ninth and 11th, while hitting smart approaches into the eighth and 14th and driving the par four 15th.
A 30 footer on the 17th had him in a share of second and when he got up and down from a bunker on the last, he was ten under on his own.
But Elvira got a very fortunate bounce at the 14th that left him five feet for a birdie and a five shot lead once again.
Korhonen two putted from the fringe at the 15th and while he gave the shot back on the next, a tee shot to eight feet on the 17th had him back in double figures after a 67.
Harding was his usual efficient self in his bogey free 66 and he holed from six feet on the third, twice that distance on the sixth and made a two putt birdie on the 11th before driving the 15th for an eagle from 18 feet.
Hanna was level par for his round after 13 holes but ended up with a 67 after he left himself a tap-in at the 14th, holed a ten footer at the next, made a putt from twice that range on the 17th and two putted the last.
Elvira was not in the mood to be caught, however, and made a left to righter from around 20 feet at the 17th to tighten his grip on the trophy.
South African Jacques Kruyswijk was at seven under, with a group of eight players ten shots off the lead.