The New Zealand superstar signed for Cardiff earlier this season on a seven-month contract in an attempt to resurrect his career following illness and injury.
It had been thought he would feature on the replacements' bench this weekend and then make a full Blues debut when Calvisano visit the Arms Park next Saturday.
But Lomu has done enough to impress Blues head coach David Young as the Blues prepare for their Italian mission, and he will start in his familiar number 11 jersey.
Lomu has not played since suffering a shoulder injury during former England and British & Irish Lions captain Martin Johnson's testimonial match at Twickenham six months ago.
Cardiff also welcome back Lomu's former All Blacks colleague Xavier Rush, who has recovered from a shoulder operation, while Wales and Lions prop Gethin Jenkins - sidelined since the summer due to shoulder trouble - begins his comeback as a replacement.