Then I thought to that place in Cyrodiil, http://www.uesp.net/wiki/Oblivion:Cloud_Top. The Ayleid http://www.uesp.net/wiki/Oblivion:Earana%27s_Notes the secrets of the Fingers of the Mountains in an engraved pillar, atop a mountain of the Southwestern Jeralls. Do you think that place could be a minor Tower, and that the Pillar could be its Stone? If not, do you think that one of the Towers is specifically associated with lightning?
Moreover, if Cloud Top is a Tower, would it be too far-fetched to think that http://www.uesp.net/wiki/Oblivion:Earana could have been a Thalmor agent, seeking information on this tower and on the ways Ayleids harnessed its power, in order to destroy it later?