The electronic orbits are quantized in a sense that only certain orbits are allowed. An electron can revolve around the nucleus in such quantized paths. No other trajectory of the electron is allowed.
Rules of classical physics do not take into account the concept of quantization of energies and angular momenta in electronic states. Classical ideas are very much inapplicable in the atomic domain and the electron revolves around the nucleus in accordance to the rules of the quantum theory (In our case, the old quantum theory) and not classical laws.