His international career started with a fifteenth place at the 1992 World Junior Championships. The following year he took his first national shot put title. In 1994 he threw past the 19-metre mark for the first time, with 19.06 metres achieved in April in his birth city. At his first World Championships, in 1997, he reached the final and placed tenth. He only managed one valid throw. In 1998 he won the gold medal at the African Championships with a throw of 19.78 metres. This was the best winning result since 1982, when Youssef Nagui Asaad threw 20.44 metres. In the same year he threw 20.01 metres when winning the Commonwealth Games held in Kuala Lumpur, and 20.29 metres in Johannesburg in September. Rarely competing in other athletics events, Lambrechts did throw 53.68 metres with the hammer (1996) and 58.60 with the discus (October 1998).