Lazy loading hibernate - spring

Question

I use Spring 3 and hibernate 3.6.3.Final. I have to entities A and B. The hbm files are:
A.hbm.xml
<hibernate-mapping>
<class name="com.A" table="A" >
<id name="A_Id" type="string">
<column name="Id" length="100" />
<generator class="foreign">
<param name="property">B</param>
</generator>
</id>
<one-to-one name="B" class="B" constrained="true" fetch="select" ></one-to-one>
<property>...</property>
</class>
</hibernate-mapping>
and B.hbm.xml
<hibernate-mapping>
<class name="com.B" table="B">
<id name="B_Id" type="string">
<column name="Id" length="32" />
<generator class="assigned" />
</id>
...
<one-to-one name="some_A" class="com.A" lazy="proxy"></one-to-one> // FIRST
<one-to-one name="other_A" class="com.A" lazy="proxy" cascade="all" > // SECOND
<formula>other_BSRC_REG_REP_MESSAGE_ID</formula>
</one-to-one>
</class>
</hibernate-mapping>
From #Service I use the following code to get entity B by id:
getHibernateTemplate().get(getEntityClass(), id)
I enabled the show_sql mode in hibernate in order to check if my lazy loading works fine. Unfortunately I don't understand them
When either FIRST or SECOND line is commented out hibernate shows exactly one query (where all of the one-to-one associations are present as join),
When both FIRST and SECOND lines are uncommented hibernate shows two queries, one to get B and second to get an A entity.
Why this happens? Is it because all of the one-to-one association can't be lazy loaded so either they are eagerly loaded as a separate query or "joined" to the original query? If so, why hibernate didn't joined on the A table twice?