This is another interesting ask the rabbi question and answer from the Beit El yeshiva website.
http://www.yeshiva.org.il/ask/eng/?id=4441G-d’s name
Rabbi Elchanan Lewis
Question:
Personally I don’t like to use the name G-d at all since to my belief it is not allowed to use G-d as well as amon or other deities. Am I wrong to prefer to use only Elokim and Kel shakkai etc and not G-d since this is also taken his name in vain according to my belief? I might be wrong, please correct me
Answer:
The Talmud [Nedarim 7b] teaches that even though the third commandment of not carrying Hashem's name in vain is explicitly speaking about an oath using any of Hashem's names, it also teaches us not to speak his name in vain at all.
There are seven names within the category of Godly names that can't be uttered in vain all of which are listed in the Shilchan Aruch [YD 176:9] and therefore when are spoken not in the context of the holy scriptures are altered as Elokim, Shakai, Kel, Tzevakot etc.
The word G o d is not of these seven names and can be uttered or written and erased without violating any Halachic restriction just as the adjectives "merciful" or "the all mighty" that allude to G o d, are not his name. [Ohr Sameach, Avodat Kochavim 2:7] .
Even though "G o d" is not one of the seven names, since it is a reference to the holy one blessed is he, many have the practice to spell it G-d to show respect to his name.
To conclude – you can use both G o d and Elokim as reference to Hashem but the other two names you wrote should be altered if not during Torah study to Kel and Shakai.