Bjorn fired a course-record 62, a round that included a 30 on the par-37 back nine. When play was halted for a second time Thursday, he led by two shots over Shane Lowry, who was 8 under with one hole left in his opening round.
The Dane made the turn in 3 under but caught fire on the inward half, playing five holes in 5 under from Nos. 10-14 highlighted by an eagle at the par-5 12th. His round equaled the course record first set by Robert Karlsson during the third round of the 2010 BMW PGA Championship.
Players dealt with rainy conditions for much of the morning in Surrey, England, but as casual water began to accumulate throughout the course, tournament officials decided to stop play shortly before 1 p.m. local time. Only half the field had begun their opening rounds when the horn blew. Play resumed after a 35-minute delay, but then was stopped again 45 minutes later because of the threat of lightning.
In addition to Bjorn, Martin Kaymer was able to take advantage of soft conditions during the morning wave. Two weeks after his triumph at TPC Sawgrass, Kaymer carded a 4-under 68 and was among a tie for fifth when play was again halted. Henrik Stenson, who has a chance to move to world No. 1 with a high finish this week, was 3 under through 17 holes, and two-time BMW champion Luke Donald was 1 under through 17 holes.
While many players were able to reach red figures before the stoppage of play, some big names got off to a slow start. The group of players at 2 over includes Nicolas Colsaerts, Charl Schwartzel and Retief Goosen. Goosen was in with a 2-over 74, while Colsaerts and Schwartzel each had one hole left to play. Sergio Garcia, who finished third at The Players Championship in his most recent start, shot a 1-over 73 after playing his first 17 holes without a bogey, and Justin Rose was 2 over after starting with a pair of bogeys.
Rory McIlroy and Ernie Els had not yet teed off when play was suspended, while several players had only completed two holes or fewer, including Rose, Lee Westwood, Ian Poulter and defending champion Matteo Manassero.
Play resumed at 3:45 p.m. local time after a delay of 1 hour, 44 minutes.