Ex-Canary Daryl Sutch, Boston triallist defender Ben Chapman and Mark Angel were making their home debuts, and Lynn started well with numerous half-chances.
Chapman shackled Hamlet's best player, the tricky and pacy David Moore.
Ryman Division One Dulwich, sporting a fetching pink and navy blue diamond shape kit, found the one-divisional gap too much to bridge, but had their best chance of the game when Moore's free-kick was tipped on to the post by Steve Wilson.
But a minute later Bloomfield finished from close range a move involving Tony Battersby and Mark Camm. And within 60 seconds Battersby set up Angel to rifle home from 20 yards.
Midway through the half Camm was fouled and the unmarked Carl Holmes headed home Angel's free-kick.
Bloomfield grabbed his second five minutes before the break, Battersby turning provider for the third time.
Either side of half-time Alex O'Brien and Craig Prendergast cleared off the line from lobs by Camm - restored to midfield and industrious as ever - and Robbie Harris respectively.
The visitors' only chance of note was Charlie Side shooting over when well-placed.
Joint boss Darren Bloodworth said: "It was a good workout and good for fitness in those hot conditions. We've achieved all we wanted to from the pre-season.
"Some people didn't think Dulwich were the strongest, but that takes credit away from us.
"St Neots was a tough one on Thursday, a bit of a battle, but Dulwich gave us more space, and we murdered them at times.
"It was good to see Daryl Sutch get through 90 minutes. He gets the ball and plays it easy, which was what we wanted.
"We hope to get Ben Chapman, although that will have financial implications. He played 40 league games for Boston last season, and linked up well with Mark Angel. They played together at Boston."
Lynn: Wilson, Jones, Chapman, Burrows, Setchell, Sutch, Camm, Holmes, Battersby, Bloomfield, Angel. Subs: Hammond, Harris, Heath-Preston, Stevenson, Fishlock, Blake, Bacon, Osborne.
Dulwich: Harwood, Ahwan, Reed, O'Brien, Ababio, Curnow, Moore, Ward, Edgar, Side, Bowes. Subs: Turley, Ball, Tilbury, Prendergast, Schoburgh.
Att: 404. Referee: Dean Hinchcliffe (Norfolk FA).