how to write...

how to write lawrence in japanese calligraphy??

There is no kanji for lawrence as it isn't a Japanese name.

You can write it phonetically in katakana like this:

ロレンス

Check out this page for translating names to katakana:
http://www2.japanese-name-translation.com/jnt/index.asp


Here's some similar threads:
http://www.japan-guide.com/forum/quereadisplay.html?0+43330
http://www.japan-guide.com/forum/quereadisplay.html?0+42681