Chinese media disambiguates the two Trudeau prime ministers with 老特鲁多 ('Old Trudeau' = Pierre) and 小特鲁多 ('Young Trudeau' = Justin) — the same 老/小 prefix trick used for the Bush presidents (老布什/小布什).
memory
Three syllables for the French-Canadian surname: 特 (tè) + 鲁 (lǔ) + 多 (duō). The 多 at the end carries the -deau ending the way 戴高乐 (Dài Gāolè = de Gaulle) handles -aulle.