In 2015, Lambrecht became the Belgian national junior champion, relegating Glen Van Nuffelen and Stijn Goolaerts to second and third places respectively. In 2016, he caused a surprise by winning the opening stage of the
Ronde de l'Isard. In the final stage he was sent in the wrong direction by the race management. The race jury recognized the error and so Lambrecht became the third Belgian to win this race after Yannick Eijssen (2010) and Louis Vervaeke (2014). Just under two weeks after his final win in France, Lambrecht took part in the
Grand Prix Priessnitz spa race with a Belgian selection. Here he managed to win the last leg, with a sloping finish on cobbles in
Jeseník, with a lead of a few seconds. At the beginning of 2017, he won
Liège–Bastogne–Liège U23 race by beating his three fellow poursuivants in the sprint. Later that year he was fifth in the
Flèche Ardennaise race, second in the final classification of the Ronde de l'Isard, eighth in that of the Tour of the Jura, he won a stage and the final classification in the Grand Prix Priessnitz spa and became second in the final classifications of the
Tour de Savoie Mont-Blanc, the
Giro della Valle d'Aosta and the
Tour de l'Avenir 2017. In 2018, Lambrecht turned professional with . In 2019, he recorded his biggest result as a professional, finishing fourth at the
Flèche Wallonne race. In April of the same year, he signed a two-year contract extension with . ==Death==