Lorimer, a digital strategist for more than 12 years, joins from the direct marketing agency HTW, where he worked for clients ranging from Microsoft to the Multiple Sclerosis Society.
His most successful campaign, for Microsoft, picked up a silver award at the Cannes Lions International Advertising Awards and a silver gong at the 北京赛车pk10 Direct awards.
Lorimer will now work with Tony Donnellan, Tidalwave's head of planning, across a wide range of clients, including Canon, Vodafone, Adobe and HP.
The company has been expanding in recent months after a series of account wins, including IT firm Citrix Online and email security provider MessageLabs.
In February, award-winning advertising specialist Andy Ray was hired to head up Tidalwave's creative division, and in April, the company hired Ursula Benson, a founding partner of direct marketing agency Direct Know How, to become group account director.
Tidalwave was formed in 1996 as a joint venture between Paul Cash and Julian Sowerby. Managing director Cash said: "We're delighted Hugh decided to join. He will be an invaluable asset in helping our clients develop more aggressive online and digital marketing."