The growth and structuring of polyelectrolyte self-assemblies (so-called "multilayers") made from a lyotropic ionene and a strong polyelectrolyte are examined in depth using X-ray reflectometry among other techniques. We show that highly ordered polyelectrolyte films may be obtained, consisting of a regular lamellar nanostructure extending over considerable distances in the films, with preferential orientation of chain fragments occurring in the films. This is in marked contrast with classical, "fuzzy" multilayers, for which no internal structure was reported so far. From our set of results, including a comparison of the structures of "multilayers" and bulk complexes, we propose that three mechanisms govern film growth and structuring: adsorption of the polyelectrolyte (governed by electrostatic balance), diffusion of the polyelectrolyte into the previously adsorbed film (which is the blurring step), and surface-constrained complexation between the polyanion and the polycation resulting from the mixing due to diffusion. Depending on whether the polyelectrolytes are capable of forming structured complexes or not, the self-assembled film will present different levels of internal organization. These findings have important implications for the general understanding of electrostatic self-assembly and for possible applications therefrom.