This article queries whether consonant sonority (sonorant vs. obstruent) and status (coda vs. onset) within intervocalic clusters influence syllable-based segmentation strategies. We used a modified version of the illusory conjunction paradigm to test whether French beginning, intermediate, and advanced readers were sensitive to an optimal "sonorant coda-obstruent onset" sonority profile within the syllable boundaries as a cue for a syllable-based segmentation. Data showed that children used a syllable-based segmentation that improved with reading skills and age. The results are discussed to support that the visual letter detection within pseudowords primarily and early relies on acoustic-phonetic cues within the syllable boundaries, whereas the syllable effect seems to be developmentally constrained by reading skills and age. (Contains 2 tables and 3 footnotes.)