A league source requesting anonymity said the hard-hitting linebacker has agreed to terms with the CFL club.
Elimimian became a free agent at noon ET on Friday but reached a deal with the Lions less than two hours later.
The six-foot, 227-pound linebacker spent time with the NFL's Minnesota Vikings and Cleveland Browns last year before returning to B.C.
Elimimian, 26, began his CFL career with the Lions in 2010 and captured the league's top rookie award that year before being named its hardest hitter in a 2011 TSN poll.
Elimimian's return further solidifies a Lions defence that last year was the CFL's best and also features all-star linebacker Adam Bighill.