This was my exact presentation of the virus. A deeply profound loss of smell and taste, with an otherwise clear nose. I did develop some significant fatigue and fogginess and a slight cough, but the complete loss of smell and taste was upsetting. The early articles about this connection back in March is what prompted us to get tested. In our cases, though, this symptom appeared almost immediately and stuck with us throughout the infection, so I don't think it's fair to generalize about when anosmia is likely within the course of the virus.